Electrical relay



Jan. 4, 1938. N. F. AGNEW ET AL 2,104,602

ELECTRICAL REL-AY Filed Sept. 16, 1955 Fig. 2.

10 AL-2%] 8b 1-;

2 Fig. 5

INVENTO'RS Norman FT Agnew Bezy'amin isbeleuz'olz TIEIH ATTORNEYPatented Jan. 4, 1938 UNITED STATES PATENT OFFICE .z,1o4.eoz amc'raroar.nanny Application September 16, 1935, Serial No. 40,728 1 claim; (01.171-314) Our invention relates to electrical relays, and particularly toelectrical relays which are connected with a source of varyingpotential, and which are adapted to pick up when and only 5 when thepotential of the source increases to a predetermined value.

One object of our invention is to provide means for preventing relays ofthe type described from picking up at lower potentials than thepredetermined pick-up potential due to the effect of shock or vibration.

We will describe three forms of relays embodying our invention, and willthen point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is 9. diagrammatic view showing ourinvention applied to a relay which controls the charging rate of abattery. Figs. 2 and 3 are detail views showing modiflcations of ourinvention.

20 Similar reference characters refer to similar parts in all threeviews.

Referring first to Fig. l, the reference character T designates atransformer, the primary I of which is constantly connected with theterminals 23 B and X of a suitable source of current not shown in thedrawing, and the secondary 2 of which is connected with the inputterminals 3 and I of a full wave rectifier R. The output terminals 5 and6 of the rectifier R are connected, through a our- 39 rent limitingresistance 1, with a battery A which may supply current to any desiredload, here shown for purposes of illustration as a lamp L. Theresistance 1 is connected in multiple with a back contact 8-4 of a relayC, and the parts are so proportioned that when the relay C isdeenergized so that the resistance 1 is short circuited by the contact8-8, the battery B will be charged at a relatively high rate, but that,when the relay C is energized so that the resistance I is not shortcircuited by the contact 8-8, the battery A will then be charged at arelatively low rate.

Relay C is intended tobe connected ,with the 45 terminals of battery Ain such manner that the potential which is impressed on the relaywinding will vary with the state of charge or discharge of the battery,and the relay is so designed that it will pick up its armature and openits back con- 50 tact 8-8 when the potential which is impressed acrossits winding is equal to the potential of the battery when the battery isfully charged. For example, if the potential of the battery A when thebattery is fully charged is 2.3 volts, the relay 5;, C will be sodesigned that it will pick up its armature and open its back contact 8-8at 2.3 volts.

It will be readily understood that when relay C is connected across theterminals of battery A in the intended manner, if the relay issubjected. to 5 shocks, it may pick up at a somewhat lower potentialthan the fully charged potential 01' the battery. Thls-is undesirableand in order to prevent this from happening, we provide means fordecreasing the energization of this relay when the 10 relay is subjectedto shocks. As here shown, these means comprise a contact D which isconnected in series with the relay winding between the terminals of thebattery, and which is so designed that it will vibrate open in responseto shocks.- The contact D may have any preferred construction, but ashere illustrated this contact comprises two cooperating contact members,one of which, 9, is secured to a fixed conductin member ID, and theother of which, H, is secured to a cantilevertype spring I2 ofconducting material, intermediate the ends of the spring. The spring I2is rigidly supported at one end and is provided at the other end with aweight l3. The parts are so proportioned that when the relay is notsubjected to shocks, the tension of the spring will cause the contactmember ll to engage the contact member 9 and thus close the contact D,but that, any shocks which would be sufficient to cause the relay topick up at a potential below the calibrated pick-up potential will causethe contact spring I! to vibrate and thus intermittently open contact D.It will be apparent that when the contact D is opened, relay C will bedisconnected from the battery A, and it follows that the relay cannotpick up due to shock unless the battery is fully charged, in which eventthe relay will pick up in the usual manner even though the contact Disat times vibrated open.

Under some conditions it is desirable to insure that contact D will notcause the relay to become released after it is once picked up. Thisresult may be accomplished by so locating the contact D that when therelay is picked up, the armature, or a member secured thereto, willmechanically 5 engage the weight I3 in a manner to prevent the contactfrom opening, as shown in Fig. 2. This result may also be accomplishedby providing the relay with a front contact 8-4 which, when the relay ispicked up, provides a low resistance shunt around the contact D, asshown in Fig. 3.

If it is desired to prevent the contact D from arcing, a high resistancemay be shunted around this contact. When this is done, the opening ofthe contact will merely reduce the operating ourrent a predeterminedamount rather than completely cut of! the supply'oi current to therelay.

It is preferable that the contact D should be built into the relay C andform a part thereof, but this contact may, if desired, be enclosed in aseparate housing which is secured to, or located in the vicinity of therelay, in such manner that the contact will be subjected to the sameshocks as it would be subjected to if it were built into the relay.

It should be particularly pointed out that while in illustrating ourinvention we have shown it applied to a relay which controls thecharging rate of a battery, our invention is equally applicable to anyrelay which is adapted to be connected with a source of varyingpotential, and which is designed to pick up at a predeterminedpotential.

Although we have herein shown and described only three forms ofapparatus embodying our invention, it is understood that various changesand modifications may be made therein within the scope oi the appendedclaim without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

In combination, a battery, a resistance, means for charging said batteryconnected with said battery through said resistance, a relay adapted topick up on a potential which is equal to the fully charged potential ofsaid battery, a contact which is designed to vibrate open in response toshocks, means for connecting said relay with said battery over saidcontact, means for preventing said contact from vibrating open when saidrelay is picked up, and a back contact on said relay connected inmultiple with said resistor.

NORMAN P. AGNEW. BENJAMIN MISHELEV'ICH. so

